DENVER (AP) — A Denver clinic accused of conducting CT scans on patients without orders from a licensed doctor has been fined nearly $3.2 million, Colorado health officials said Monday.

About 150 people per week were getting scans at Heart Check America and were exposed to “potentially unnecessary radiation doses without a doctor’s involvement,” said Brian Vamvakias, X-ray certification unit leader at the Colorado Department of Public Health and Environment.

The health department said the fine is the largest ever imposed by the state’s radiation program inspectors.

Officials said the company abruptly closed its Denver clinic in May after the state began investigating in April. State health officials said the clinic stopped returning calls and when department representatives went to the clinic’s office on May 5, three days after getting a notice of violation, the office was empty.

The state health department said Heart Check America also operates or operated clinics in Nevada, Illinois, New York, South Carolina, California, and Washington, D.C. The company’s website was down Monday and a phone number listed for the Nevada office wasn’t working.

Joyce Goldsboro, an inspector with the X-ray certification unit of the state health department, said officials are not aware of any cases where someone was harmed by having a CT scan at Heart Check America’s Denver clinic.

The operators of Heart Check America, Sheila Haddad, David Haddad and Lisa Haddad, were served a notice of the fine against them last week at their home in Tinley Park, Ill., the state department said. Phone numbers listed for their address were either disconnected or not in service.

Todd Kaplan, the project director of Heart Check America’s Denver clinic, did not immediately return a call for comment from The Associated Press.

“They stopped all communication with us, and we were left with no choice but to proceed with escalated enforcement and assess these penalties,” Vamvakias said in a statement.

Those named in the violation order have 30 days to pay the fine or appeal and request a hearing. The fine covers nine citations, including failure to have a state-licensed physician supervise the clinic’s CT scanner, exposing patients to scans without a written order from a doctor, and failure to monitor employee’s radiation exposure.

Warren Smith, a spokesman with the state health department’s Hazardous Materials and Waste Management Division, said other states where Heart Check America conducted business are also investigating but Smith did not have additional details.

The fine, if it is paid, will be put in Colorado’s general fund budget, Smith said.